TM 11-6625-2948-14+P
e. The Repeller Voltage. AC voltage appearing across
The collector voltage of 1A4Q3 is set initially (before
1A5Q1 and 1A5Q2 oscillate or the time delay is over) by
1A5CR5 to 1A5CR8 and applied to the voltage regulator
BIAS ADJ resistor 1A4R4. Resistor 1A4R4 is the base-
network 1A3CR8, 1A3CR9 to 1A3CR12, 1A3Q2 and
emitter circuit of 1A4Q2; hence it sets the voltage for the
1A3Q3. 1A3CR8, 1A3CR9 to 1A3CR12 are zener diode
collector of 1A4Q2 or emitter of 1A4Q3. Initially the
which establish a reference voltage for the regulator 1A3Q2
emitter of 1A4Q3 IS set as approximately 12V so that
and 1A3Q3 are used in a Darlington arrangement to provide
1A5Q1 and 1A5Q2 do not oscillate. (The emitter to base
the necessary regulation. The ground repeller supply is
voltage of 1A4Q3 is thus < 0.7 volts. ) The base voltage of
referenced to the -1250V beam supply.
1A4Q3 is determined by the output of voltage regulator
1A4U3 which is a monolithic Integrated circuit. The
f. +40V Supply for Control Circuits (Fig. 5-7). The bridge
voltage between the NON-INVERTING (pin 3) and
----
rectifier 1A5BR1 rectifies the ac voltage across pins 11 and
INVERTING (pin 2) inputs of 1A4U3 IS amplified internal-
ly by 1A4U3 and appear< at pin 6, which in turn is con-
nected to the base of 1A4Q3 through load resistor 1A4R9.
amplifier 1A5U1 whose output floats at
operational
Pin 10 of 1A4U3 is biased with resistors 1A4R16 and
-1250V. The output of the operational amplifier is con-
1A4R17 such that the regulator does not regulate initially.
nected to the inverting input (pin 2) of the operational
The junction of 1A4R16 and 1A4R17 is approximately
amplifier and the non-inverting input is floating and can be
varied from 0 to 32 volts (32 volts appearing across zener
0.8V initially. When the delay time is over, this junction
diode 1A5CR15) by resistor 1A5R5 and thus the entire
voltage changes to zero volts and the regulator starts to
+40V suppIy floats at -1250V.
regulate. The output at pin 6, which is determined by the
voltage difference between pins 2 and 3, is such that
1A4Q3 conducts and in turn 1A5Q1 and 1A5Q2 start to
(Fig. 5-2 and 5-2.1)
oscillate. The amplitude of the oscillations is adjusted by
1A4R21. (When 1A4R21 is adjusted, the base voltage of
The klystron filament is supplied with regulated dc voltage
1A4Q3 varies and this in turn varies the base current of
to minimize drift and incidental amplitude and frequency
1A5Q1 and 1A5Q2 and hence the amplitude of the oscil-
m o d u l a t i o n . The klystron filament supply consists of
Iations.) Voltage reference for pin 2 is derived from the
bridge rectifier 1A3BR1 and voltage regulator 1A3U1. It is
fixed voltage regulator 1A4U2. Constant voltage IS main-
referenced to the -1250V
beam
supply.
The
filament
tained at pin 6 and hence that of the oscillations amplitude
voltage is adjusted to 6.3V by potentiometer 1A3R1.
by 1A4U3 which senses any variation of the difference in
voltages between pins 2 and 3. Pln 2 is fixed by the resistor
network 1A4R19, 1A4R21, and 1A4R22 and at pin 3
v o l t a g e is derived by feedback network 1A4R18 and
The power supplies are provided with three adjustments
1A5R7. If there IS any variation at pln 3 due to load or line
which are described below:
voltages, the regulator will correct all changes through its
feed back loop and maintain a constant amplitude of
oscillation. 1A4CR1 IS added for the protection of 1A4Q2
control
1A4R21
sets
the
operating
point
for
control
and diodes 1A5CR1 to 1A5CR4 are added for the protec-
amplifier 1A4U3 which maintains the beam power supply
tion of 1A5Q1 and 1A5Q2.
at its set value.
c. High Voltage High Frequency AC Voltage.
b. -1850 ADJ CONTROL. The-1850 ADJ control 1A3R2
sets the operating point for regulator 1A3Q2 and 1A3Q3
is stepped up through transformer 1A5T2 to suitable
which maintains the repeller power supply at its set value.
values.
d. Beam Power Supply. High voltage fast switching rectifier
C U R R E N T ADJ control 1A5R5, which has a range of
diodes 1A5CR9 to 1A5CR12 rectify the high voltage ac
approximately 32 volts, adjusts the beam current through
appearing across pins 8 and 10 of transformer 1A5T2.
the klystron. The beam current is measured by monitoring
After suitable filtering, it is applied to the klystron cathode
the voltage across 1A5R8 which appears between 1A4TP2
(-1250V).
and 1A4TP4.